Boring machine



Sept. 30, 1947. K. F. GALLIM RE 2,428,309

BORING MACHINE Filed March 15, 1945 '10 Sheets-Sheet 1 K. F. GALLIMORE BORING MACHI'NE Spt. so, 1947.

10 Sheets-Sheet 3 Filed March 15, 1945 K. 'F. G ALL'IMQRE BORING MACHINE Filed March 15, 1945 Sept. 30, 1947.- K. F. GALLIMORE BORING MACHINE Filed March 15, 1945 1o Sheets-Sheet 5 TTO RQLQ J K. F. GALLIMORE Sept 30, 1947.

I BORING MACHINE Filed March 15, 1945 1Q Sheets-Sheet 7 m T .N I m 3 N m g H m n T -l WW N A L MN J.

Sept. 30, 1947. v K. F. GALLIMORE' BORING MACHINE Filed March 15, 1945 10 Sheets-Sheet 9 UNITED STATES PATENT OFFICE BORING MACHINE Keith F. Gallimore, Fond to Giddings & Lewis M du Lac, Wis., assignor' achine Tool 00., Fond Application March 15, 1945, Serial 20 Claims. (0117-3).

The present invention relates generally to improvements in boring machines, and has particular reference to machines of the type commonly known as horizontal, boring, drilling and milling machines.

One of the objects of the present invention is to provide, in a horizontal boring, drilling and milling machine, a novel drive for the main conventional operating units, i. e., the work saddle, the work table andthe spindle headstock, which has a greatly improved versatility and flexibility in operation, and which more particularly is adaptable to effect selective operation of the units either individually or i various combinations, whereby to enlarge the variety of machine operations that can be performed and to increase the general usefulness of the machine.

Another object is to provide a new and improved feed drive which comprises two reversible variable-speed drive motors operable selectively to translate the three main units either individually or in combinations of two, and independently in either direction and at varying feed rates, one motor selectively serving the table and the other motor selectively serving the saddle and the table. As a result, each of the units may be operated with complete independence of movement as to direction and rate, either individually or jointly with any one of the other two units so as to obtain all of the motions required for the various cutting operations to be performed by the machine.

A further object is to provide a new and improved feed drive which affords a much wider feed range and a much greater number of feed changes than has been attainable heretofore in conventional drlves utilizing feed-change gearing.

Another object is to provide a novel feed drive which avoids the use of complicated feed-change gear boxes and gear shifting devices, with their inherent limitations as to the available range and number of feed changes, and which specifically comprises a reversible variable-speed electric drive motor adjusting the two-speed transmission.

' for predetermining the apparent as the description tional views taken 2 selection and limiting the extent of travel of the various units, and of interlock means for preventing improper functioning of the machine.

Further objects and advantages will become proceeds.

In the accompanying drawings,

. Figure 1 is a front elevational view of a machine embodying the features of my invention.

Fig. 2 is a plan view.

Fig. 3. is a left end view.

Fig. 4 is a right end view.

Fig. 5 is a fragmentary transverse vertical sectional view taken along line 5-5 of Fig. 1, and illustrating the work support inside elevation.

Fig. 6 is a fragmentary front end elevational view of the work support.

- Figs. 7 and 8 are fragmentary detailed secrespectively along lines 'l-l and B-8 of Fig, 5, and illustrating clamping means for the work support.

' Fig. 9 is a fragmentary horizontal sectional view of the feed transmission taken substantially along line 9-9 of Fig. 4.

'Fig. 10 is a fragmentary front elevational view on an enlarged scale of the control means for the feed transmission.

Fig. 11 is a transverse vertical sectional view taken along line ll-H of Fig. 9, and illustrating two clutch mechanisms forming part of the feed transmission.

Fig. 12 is a fragmentary vertical sectional view taken along line l2-l2 of Fig. 10.

Fig. 13 is a fragmentary vertical sectional view taken substantially'along line l3-l3 of Fig. 12.

Fig. 14. is a diagrammatic representation of the feed transmission for the various machine units.

Fig. 15 is a front view, on an enlarged scale, and partially in section, of a pendant control panel for the machine.

Fig. 16 is a fragmentary sectional view taken along line Iii-l6 of Fig. 15.

Fig. 17 is a diagrammatic representation of a hydraulic operating system forming part of the feed transmission.

Fig. 18 is a diagrammatic representation of certain electrical control circuits for the machine.

Fig. 19 is a diagrammatic representation of certain electrical control circuits for the feed drive motors.

The invention is applicable to boring machines of various types having one or more movable elements adapted to be employed in difierent combinations and to be boring, drilling and milling machine of the table type. In the particular form disclosed, the machine comprises a main bed or frame which is provided along its upper side edges with longitudinal guides or ways 2 Mounted on the ways 2 for horizontal translation longitudinally of the bed I is a saddle 3' which constitutes part of a work support 4, and which is provided on the top with horizontal transverse guides or ways 5. A work table 6 is suppcrtedon the ways for horizontal translation transversely of the bed I.

Rigidly mounted on one end of bed i is an upstanding column 1 provided with vertical guides or ways 8 on which a spindle headstock 9 is supported for vertical translation. In the present instance, the headstock 9 comprises a main horizontal spindle I0 and a parallel auxiliary spindle H, both spindles projecting from the side adjacent the work support 4 for attachment of tools (not shown) adapted to operate on work mounted on the table 6.

Removably and adjustably mounted on the ways 2 at the other end of the bed I is an upstanding column or support 12 provided with guides or ways 13 on which an end block or tailstock l4 is adapted to travel synchronously with the headstock 9. The tailstock l4 carries a suitable support 15 adapted to bepositioned in axial alinement with the main spindle l0, and to coact therewith in supporting a suitable tool bar or arbor (not shown).

The details of the main operating units of the machine, i. e., the saddle 3, the table 6, the headstock 9, and the tailstock l5, per se form no part of the present invention, and in the present instance are substantially the same as the corresponding parts disclosed in my prior Patent No. 1,858,491, issued May 17, 1932.

The present invention relates primarily to a new and improved power feed drive and transmission which is available to translate any one or more of the various main units 3, 6 and 9 independently of each other at varying rates of feed and each in either direction so as to increase the flexibility and range of usefulness of the machine. In general, the power transmission comprises a plurality of terminal drive shafts suitably connected to the various units, and adapted to be selectively connected through high and low speed mechanisms to a plurality of reversible and variable-speed electric drive motors. By selectively adjusting the speed-change mechanisms and the speeds of the motors, a wide range of feed rates is available. By connecting the speed mechanisms selectively to the drive shafts, various combinations of the units may be operated for different machining requirements. By selectively controlling the direction of rotation of each of the electric motors, the direction of translation of each unit may be independently determined.

Shaft connections to units The terminal drive shafts (see Fig. 14) include a shaft l6 having a lead screw in threaded engagement with a non-rotatable nut I1 anchored in the saddle 3 for translating the latter along the ways 2, a second shaft [8 having longitudinal splines IS in slidable engagement with a gear transmission 29 for driving a rotary nut 2i anchored in the saddle 3 and in threaded engagement with a non-rotatable lead screw 22 carried by the table 6 to translate the latter along the ways 5, and a shaft 23 rotatably anchored on column 1 and having a lead screw 24 in threaded engagement with a nut 25 fixed in the headstock 9 to translate the latter vertically along the ways 8. The shaft 23 is connected through bevel gears in thetailstock i4. Consequently,

4 26 and 2'! to a spline shaft 28 rotatably anchored in and extending I. A bevel gear 29 is slidably splined on the shaft 28 and meshes with a gear 30 on a lead screw 3| rotatably anchored in the column I2. The screw 3| is in threaded engagement with a nut 32 fixed the lead screws 24 and 3| are driven simultaneously to translate the headstock 9 and the tailstock l4 in exact synchronism.

A vertical spline shaft 33, rotatably anchored on the column I, is connected to a suitable source of power, such as an electric motor 34, and extends slidably through the headstock 9 and is therein adapted to be connected through a suitable variable-speed transmission (not shown) to the spindles l0 and H selectively to rotate and axially translate the latter.

' Thegear transmission 29 for the table 6 consists of a unitary structure having an enclosing housing 35 removably mounted in the saddle 3. The spline shaft 18 extends slidably through a spiral gear 35 journaledin the lower portion of the housing 35, and the nut 2| is suitably journaled in the upper portioncf the housing. Meshing with the spiral gear '36 is a spiral gear 31. A gear 38, rotatable with the gear 31, is connected through a cluster gear 39 on a shaft 40 to a gear 4 l rotatable with the nut 2 I.

The various units-3, Band 9 may be translated manually. In the case of the tablet, the shaft 40 extends to the front of the work support 4 and is connected through a train ofgears 42 to 45 to a transverse shaft 46 journaled in and extending through the saddle 3. Suitable operating handles 41 are secured to opposite end of the shaft 45.

The means for manually translating the saddle 3 comprises a tubular shaft 48 journaled in a bearing bracket 49 on the front of the bed I adjacentthe right end. One end of the shaft 48 is connected through bevel gears 50 to the shaft l6, and the other end is connected through a train of gears 5i to a stub shaft 52 journaled in and extendin'g'to the front of the bracket 49 for engagement by a hand lever 53.

' The manual actuating means for the headstock comprises a shaft 54 supported in a gear housing 55 within the bed I' and extending axially through the shaft 48. A bevel gee-r56 on the rear end of the shaft 54 meshes with the gear 26 to establish the connection with the screw shaft 23. At the forward end, the shaft 54 is connected through a train of gears 5'! tea stub shaft 58 journaled in and extending to the front of the bracket 49 for engagement by a hand lever 59.

The gearing arrangement of the hand feed for each unit is such that directional or natural control-is obtained. Thus, clockwise rotation of the right-hand lever 41 will translate the table 5 rearwardly, of thelever 53 will translate the saddle 3 to the right, and of the-lever'59 will elevate the headstock ll. Counterclockwise rotation of these levers will effect translations of the respective units'in the reverse directions.

Each of the units3, 6 and 9 may be clamped in position of adlustmentwhen not being translated. Thus, clamps 63 and 5! are provided respec'tively' for the saddl 3 and table 6, and are operable by hand levers 62 and 63 (see Figs. 5 to 8).

Selective drive connections The feed transmission, as stated, is such that the main operating units 3,5 and 9 of the'machine may 'be'connected selectively, either inlongitudinally through the bed on of the terminal shafts to one of the power shafts, the associated unit can be translated singly while the other two units are stationary.

The arrangement is simple and comparatively inexpensive in that only two drive motors are required to supply the power for translating the three units singly and in selected combinations. At the same time, the direction of translation of each unit can be independently controlled. The arrangement greatly increases the usefulness of the machine. For example, translation of the headstock and the table can be utilized for profiling operations performed with face milling cutters to machine unsymmetrical surfaces. These same movements can be used for profiling operations with side milling cutters which are caused to follow scribed lines of contour by selective changes in direction and rates of feed. In general, milling operations can be performed by translating the headstock and table units, and boring operations can be performed either by saddle unit. In the bination, a vertical cut is provided by the headstock feed and depth control is obtained by the saddle feed. In the second combination, the table may be translated to provide horizontal milling cuts and the saddle unit may be fed to control the depth of cut,

In the preferred form, the selective drive means is housed in the transmission case 55 which is mounted in the bed I by means of pads 66, and which is formed with an intermediate wall 61 defining two compartments 68 and 69. The power shafts $4 and 65 extend into the transmission case 55 in parallel relation to each other and to the shafts l6, l8 and 28 and are journaled in suitable bearings in the intermediate wall 61 and one outer side wall 10. Intermediate the walls 6? and 79, the power shafts 6t; and 65 are longitudinally splined, and respectively support shiftable cluster gear members H and 72.

The member H comprises axially spaced gears 13 and M which are separated by an annular groove 75, and which are located between and movable in opposite directions respectively into meshing engagement with two gears 16 and 11. These gears are fixed respectively on stub shafts ends of the Similarly, the member 12 comprises axially spaced gears and BI which are separated by an annular groove 82 and which are located between and movable in oppothey support the bevel gears 50 and 21.

It will be evident that by selective shifting of the members H and 72, various drive connections can be established. Thus, upon shifting only the member H to the right to engage gears 14 and 16, the feed transmission for the saddle 3 alone will be established; upon shifting only the member II to engage the gears 13 and 11, or the member 12 to engage the gears 17 and 89, the feed transmission for the table 6 alone will be established; upon shifting only the member 12 tothe right to engage the gears 8| and 83, the feed transmission for the headstock 9 only will be 72 to the right,

right and the member and the table will be Any suitable means may be provided for shifting the members H and 12 to obtain the desired machine operation. In the present instance, this means is shown as comprising two shifter shoes engaged by a lever pinned on the rear end of I a transverse shaft 9|.

The rod 88 is formed with a, transverse notch 98 engaged by the lever end of a transverse shaft 12 to the left, the saddle 99 pinned on the rear 7 V 62. A stub shaft "13- is jourtheforward' end with an the feed drive to thetable' fi Movement of the lever Ifi tintow the right-handpositien will shift th'e 'member I2 to the right to-engage the feed drive-to the. headstock- 91 When the lever I04 in the central or neutral position, all drives frontthepower shaft 85 are disconnected.

Interlock means is provided for preventing simultaneous connection of the terminal shaft IS' for'the table Iito'both power shaftsM and 65. In the present instance, this means comprises two axially alined rods IIiI'andat their opposite ends in the control housing 49. The adjacent ends of the shafts I01 and I08 are independently slidable and-disposed for end'abutting engagement-in a-bore H19- formed in a lug I II'Idepending into a longitudinal channel II I in the-underside of the-housing 49. Two dogs II2. and H3 are pinned respectively depend downwardly for engagement by cams I I4 and H5 fixed on the shafts 9d and I133. The cams N l-and H5 are similarlyshaped but oppositely disposed; andeach has a rise formed with a'flat' abutment surface I'IBc It will be noted thatthe shaft 94 may be rotated counterclockwise and't'he shaft I03 may be rotated clockwise atiany'time' toconnect the saddle 3Iand the headstockfi'respectively for translation withoutinterference by the dogs H2 and n3; However, if the shaft 94" is rotated clockwise to connect the terminal shaft It for the table 6 to the power shaft 64, thecam IId'will engage the dog M2 to shift the rod It)? to the right intosubstantially abutting engagement with .the rod- I08, and the. abutmentface IIE on the cam will" lock the rod lillfinthis position. Asa result, the other rod I08 'is constrained against leftward movement, and through the dog I I3 and cam I I5 williprevent direction to connect the shaft I8 with the power shaft 65; Likewise, assuming that. themember 1 II'isnot in the left-hand'position, upon rotation of the shaftIII3 in a counterclockwise direction, the-cam H5 willengage the dog H3 to shift the rodclliii'to the left into position to preventclockwiserotationof the shaft 95. In either case, if one-of themembers 'II and I2 is shifted to the left, the other member cannot be shifted to the leftto connect the feed drive for thetable 6, but can; occupy only the neutral position. or be shifted to the right.

Feed range cda'ustment obtain a greatly increased lrange of feeds; each of the mechanisms I I I. and f I I8. constitutes: asJtransmission providingihigh: and low superimposed speed ranges. Thespeed-zrratio;ofthetransmis sions iis such: that in. changing from onelspee'dL to the rods I01 30 and?lfifiiforslidable movement therewith, and,

and are arranged for lflfi slidably supported speed range of each range to-theother there is continuity in the pro-- gressive sequence of feed rate, tordue at the-lowest motor speed utilized. Thus, different ratios may be provided dependingon the requirements. In some instances, the ratio may advantageously be approximately equal to the speed range of the feed motors H9 and I20. For example, if the motor speed range were 1, and the transmission speed ratio also were 20:1, the power? shaftsxwould be operable at speeds from 1 to 21) R; P' M; when the low speed connection isfflestablishe'd and at speeds from 20 to 400 R. P, M'. when" the high speed connection is established, merely by. varying the speeds of their drive mo- "tors. In other instances, it may be desirable to provide. a speed ratio less than motors,. such for example as 1221 for a maximum motor speedrange of H I feed motor might be employed for the-10W speed range setting of the transmission, and only the upper 60 percent: of themotor speed range would be employed for the high speed-range setting. The. two-speed mechanisms or transmissions "H1 and H8 are housed in the bed I adjacent the right end; and comprise two spaced bearing plates HI and I22 constituting opposite end sections.

These platesare rigidly supported in position by.

a plurality of pads I23 secured to the internal structure of th'ebed I, J ournaled in and extending between the plates i2! and I22, in parallel relation to each other and to the power shafts 6d and BE, are two shafts I213 and I25 alined with sand coupled respectively to the motors H9 and Izthandltwoshafts I26 and-I21 alined with and coupled to the. power shafts. Two multiple clutchesl28 and 25 are provided for connecting the outlet shafts I26 and I21, each selectively E -throughhigh and low speed gear transmissions,

rotation of the shaft I03. in a counterclockwise respectively, to the associated inlet shafts I21 and I25;

Thespeed transmissions I I1 and II8 preferably are alike'in construction. Considering first the drive forthe shaft 6 3, the clutch I28 comprises a sleeve I39 slidably splined on the shaft I26 for rotationtherewith, and having Opposite end clutch elements I31 and IE2, and an intermediate annular groove I33. engageable by a shifter shoe I34, Freely'rotatalole on the shaft I26 in position for engagement respectively by the elements I3I and I32 upon movement of the sleeve I30 respectively in-opposite directions are two driving clutch elements I35 and'ItB. The element I36 is rigid witha coaxial gear I37 meshing with a gear I38 on the shaft IM to constitute the high speed gear drive. Rotatable on theopposite end of the shaft I2fi. is.a gear I39 meshing with another gear I40 on.-the:shait I23, the speed ratio of these gears being the same as that of the gears I3! and I38. The clutch element I35 is rigid with a coaxial internal gear II which meshes with a pinion I42 carried eccentricallyby the gear I39 and meshing with a stationary internal ring gear I43. The gear-IIiI has a, slightly greater number of teeth than-rthe gear -Ill3'so that the arrangement has a differential action by reason of which the gear III is rotated'at a much slower speed than the gear I39. For example, if

speed ratio of the high speed drive to the low speed drive will be 2021. Since the other transmission I-2I8iis the same in construction, it will not be described in detail, except tostate that thewith adequate that of the feed 2011. In this case, the full the gear I 53 has fifty-' seven teeth and the gear III has sixty teeth, the- 9 clutch sleeve in this instance is engaged by a shifter shoe I44.

The clutches I28 and I29 are selectively adjustable under remote control, and preferably from a centralized control station, such as a pend- 1 ant I45 movably suspended from the column 1 at the front of the machine. The clutch adjusting means may be hydraulic, and the control therefor may be electric. In the present instance, two reversible hydraulic actuators I46 and I41 are mounted on the end plate I2I, and have piston rods I48 and I49 slidable in the plates I2I and I22 and connected respectively to the shifter shoes I34 and I44.

Hydraulic fluid under pressure may be supplied i to the actuators I46 and I41 from any suitable source (see Fig, 17), such as a pump I50 having an intake line I5I taking fluid from a reservoir I52, and an outlet line I53 including a working pressure relief valve I54 for maintaining a, con-2'- stant predetermined pressure therein. The pump I56 is driven by an electric motor I55 mounted on the right end of the bed I.

The pressure line I 53 is adapted to be connected in parallel respectively by two reversing 5 to the actuators I46 and I41.

supply line I60 leading to one end of the actuator "J 5 I46, and to connect a line I 6| from the other end of the actuator to a drain line I62 discharging to the reservoir I52. The other valve I51 is of the nects the pressure line I53 to a line I63 leading to one end of the actuator I41, and a line I64 from the other end of the actuator to a drain line I65. Both valves I56 and I51 are normally biased to effect movement of the actuators I46 and the right, and hence to actuate the clutches I28 and I29 in a direction to establish the high-speed drive range.

The valves I56 and I51 are shiftable selectively into reverse position upon energization of two solenoids I66 and I61 operatively associated with the respective valve plungers. energization of the solenoid I66, the low speed drive range for the saddle 3 or table 6 will be established, and upon energization of the solenoid I61 the same range for the table or the headstock 9 and tailstock I4 will be established.

Electrical control circuits and operation Electric power three supply menus or lines L1, L2 and L3 nor- I47 to $210 Thus, upon 10 plied to the feed motors H9 and I20 through the respective pairs of leads I68, I69 and I10, I1I appearing in Fig. 18.

To condition the machine for operation, it is necessary first to start the oil pump motor I55 o as to build up pressure in the hydraulic system. The motor I55 is started by momentarily closing a push button run switch I12 to complete a circuit across the lines L1 and L2 through a relay coil OP. Upon becomin energized, the relay coil OP closes sealing contacts 0P1 to establish a holdin circuit across the switch I12, and closes contacts 0P2 to connect the oiLpump motor I55 to the lines L1, L2 and L3. Interposed in the circuit in series with the sealing contacts 0P1 are a push button stop switch I 13 and a master stop switch I14. Opening of either of these switches will stop the entire machine operation. The re- L2 selectively through one or the other of forward and reverse relay coils IF and IR as deter mined by the setting of a selector switch I11. For forward operation, the circuit is completed from the line L4, through the pressure switch I 15, normally closed contacts I18 of a push button stop switch I19, the run switch I 16, the selector switch I11, and the relay coil IF to the line L2. For reverse operation, the circuit is the same except that it is completed from the selector switch I11 through the relay coil I R.

Upon becoming energized, the relay coil IF closes sealing contacts IF]. to establish a holding circuit, opens interlock contacts IFz in the circuit for the IR, closes contacts IFs trol circuits for the feed motors H9 and I20.

Likewise, upon becoming energized, the relay coil IR closes sealing contacts IRi, opens inter- IR2, closes'motor contacts IR: to institute reverse operation of the motor 34, and closes contacts IR4 to condition the feed motor circuits. It will thus be evident that the feed motors H9 and I20 cannot motor I55 is in operation.

The circuit for the spindle motor 34 may be conditioned for continuous operation as just described, or for intermittent or inching tion under the control of the run switch I16. this end, the push button stop switch I19 has a second set of contacts I in the shunt circuit across the run switch I16 and alternate contacts paralleling the contacts I18. For continuous operation, the stop switch I19 is adjusted to close the contacts I18 and I80, thereby enabling completion of the holding circuit by either of the contacts IFi or R1. For intermittent operation, the stop switch I19 is adjusted to open the contacts I18 and I80 and close the alternate contacts I8I, thereby permitting completion of the energized respectively to -mounted 'on'the column I for engagement gizing circuit only through the run switch- I16.

Consequently, the spindle -motor 94 will operate only when the run switch ITIiis closed, and will stop when the switch is released.

'Assuming thatthe-electronic power and control circuits for the feed motors H9 and 120 are CR2 and FPR2 will be enerclose contacts CR21' and FPR21, thereby conditioning the starting control operative, relay rcoils circuit forthe motor II9; Similar relay coils in duplicate power and controlcircuits (not, shown) are operable to close correspondingcontacts CR31 and FPR3-1 in the starting control circuitfor the other' feed motor I 20.

' -As in the case ofthe spindle motor 34, each of the feed motors I I9 and I20 is adapted to be conditionedselectively for operation either continuously or intermittently and in either direction. More'specifically, the direction of operation of the motors H9 and I20 is controlled respectively by selector switches I82 and I83. In one position of the selector'switch I82, the feed motor I I9 will be operated to translate the saddle 9 to the left or the table It forwardly. In the other position of the switch I82, the movements of the saddle and table will be reversed. Likewise, when the switch I83 is in one position, the motor I20 will operate to elevate the headstock 9 or translate the table 'B'forwardly. When the switch I83 isin the opposite position, the motor I20 will lower the headstock or translate the table rearwardly.

' The feed motor 'I I9 is adapted to be'started by closing a'pus-h button run switch I84 to complete a circuit across the lines L and L2 through a stop switch "I 85,the selector switch I82, and one or the other of forward and reverse relay coils 2F and 2R. If the relay coil 2F is energized, it will close sealing contacts 2F1, open interlock contacts 2P2 inthe circuit for the coil 2R, and close starting contacts -2F3 and 2F; in the electronic power cirsuit for the feed motor I I9. Likewise, if the relay 2B. is energized, it will close sealing contacts 2R1, open interlock contacts 2B: and close starting contacts 2R3 and 2R4 in the electronic power circuit for the feed motor H9.

The stop switch I85 is similar to the switch I19 for the spindle motor '34, and comprises two sets of contacts I86 and I8? adapted to be closed so as to enable theestablishment'of a holding circuit, or alternate contacts I88 adapted to be closed to .permit establishment of the energizing circuit only throughtherun switch I84.

The starting circuit for the second feed motor I20 is similar'to that for the feed motor II9. To start the second feed motor, a push button run switch I89 is depressed momentarily to complete acircuit "acrossthe lines L5 and L2, through a stop switch I90, the selector switch I83, and one or the other of forward and reverse relay coils 3F and 313.. If the relay 3F is energized, it will close sealing contacts 3Fi, open interlock contacts 3P2, andclose motor starting contacts 3E3 and '3F4. If 'theirelay 3B is energized, it will close sealing contacts 3R1, open interlock contacts 3R2 and :close motor starting contacts 3R3an'd "3R4. The stop switch I90 has contacts I9I and I92 adapted'to be closed for continuous operation, and alternate contacts I93 adapted to be closed for intermittent operation.

Suitable limit switches are actuatable by the saddle, table "and headstock units 3, B and I at the ends of their respective movements to stop the feed motors H9 and I210. These comprise limit switches LS-5U and LSSD (see Fig. 4)

by '15 land,

spaced cams I95 on '3; and limit switches LS'IF and LSlR (see Fig. '6) mounted on the saddle for engagement by the drive is to the presented by spaced cams 194 on'the' headstock*9; limit switches LSSL and LSGR (see Fig. '1) mounted bed I for engagement by the underside of the saddle spaced cams I96 on one side of the table 6. The

limit switches are appropriately connected in series with the motor starting relay coils, i. e., LSBL' and LS'IF with the coil 2F, LSBR and 1.6112. with the coil 2R, LSSU and LS'IF with the coil 3F, andLSSD and LS'IR with the coil 3R. Only one pair of limit switches is operatively connected in the circuit for each direction of motor rotation, and to this end, double acting selector limit switches LS8 and LS9 are mounted on the front of the bed I for engagement respectively by cams I91 and I-98 on the hand levers 95 and I04. The arrangementis such that'when the feed drive fromthe motor 9 is connected to the saddle 3, the table limit switches arebypassed, and when table 6, the saddle limit switches are bypassed by the switch LS8, in the circuits for the coils 2F and 2R. Similarly, the limit switchLS9 is actuated to bypass the table limit switches when the headstock 9 is operated,

and to bypass the headstock limit switches when the table 6 is operated, from the motor I20. Before turning to the feed motor power and control circuits, it is to be noted that the valve operating solenoids I60 and I6! are adapted to be connected across the lines L1 and L2 by closing respectively switches I99 and 200.

Thefeed motor H9 has an armature 20I, a series 'fie1d'202 and a separately excited field 203. The two sets of main contacts 2F3, 2F4 and 2R3, 2R4, which are controlled by the relay coils 2F and 23, respectively, form part of a reversing contactor adapted to connect the motor armature 20I reversiblyacross the lines I09 and IE9.

The usual dynamic braking resistor DER is arranged to be connected across the motor armature 20I by normallyclosed auxiliary contacts 2DB1and 2DB2. These contacts are controlled by a relaycoil2DB adapted for connection across the lines L5 and L2 through normally closed contacts 2F5 and 2R5 controlled by the relay coils 2F and 2B. When either of the relay coils 2F or 2R. is energized, the circuit through the coil 2DB. is interrupted and, consequently, the contacts-2DB1 and 2DB2 are open. Whenboth coils 2F and 2R are deenergized, the coil 2DB is energized to close the contacts 2DB1 and 2DB2 and thereby effect dynamic braking of the motor I I9.

A similar dynamic brake resistor DBR (Fig. 18) .isprovided for the second feed motor I20, and is controlled by a relay coil SDB adapted for connection across the lines L5 and L2 through normally closed contacts SF5 and 3R5 operable by the relays 3F and 3B.

Attention may now be given to the electronic circuits (Fig. 19) employed in supplying current to the feed motors II9, I20 in a manner to accomplish adjustment of their speeds and the other control functions heretofore noted. The circuits for but one of the feed motors H9 is shown in Fig. 19, since those for the other may be-a duplicate. The particular circuit shown in Fig. 19 is included as a unit under the name Thy-Mo-Trol and complete analysis will be found in a paper Thyratron Motor Control Messrs. E. E. Moyer and H. L. Palmer at the June 21-25, 1943, meeting in Cleve- Ohio, of the A. I. E. E. Accordingly, sim- 208, 2| are connected to the opposite end terminal through a conductor 242. The cathodes of the thyratrons 201, 203 are connected to the midpoint of the transformer secondary 296 through the motor armature Zill, whereas the cathodes of the other pair of thyratrons 2G9, 2H3 are connected to this mid-point through the field 293. Heating current for the cathodes of the pairs of thyratrons 201, 298 and 239, 2:0 is supplied from respective additional windings 2| 3, 2M of the transformer 204.

The amount of current passed :by the pairs of thyratrons 207, 208 and 299, 2! is, as customary in thyratron circuits, controlled by varying the phase of their grid bias with reference to the phase of the anode or plate potentiometer. In this instance, the necessary shift of grid voltage is accomplished through the use of conventional inductance-resistance bridges in which the in ductan-ce is a variably saturable reactor. In the particular circuit shown, the bridge for the grid circuits of the armature-supply thyratrons 201, 208 includes a saturable core reactor 205, while that for the field-control thyratrons 2%, 263 includes a similar satura'ble core reactor 2 l6. Current is supplied to the bridges from a potentiometer 217 connected across supply lines L1, L2, and resistors 64R and SEE constitute the resistance legs Connected across the output terminals of the bridge, including the reactor 2 I 5, is a transformer primary winding 2! 8 inductively coupled with a center tapped secondary winding Zit connected in the grid circuits of the thyratrons 20?, 283. Similarly, a transformer primary winding 2E9 across the output of the other bridge is inductively coupled with a :center tapped secondary winding 220 and the grid circuits of the other pair of thyratrons see, em. The saturation of the core for the reactor 2l5, and hence the inductance of the latter, is controlled by variations in direct current passed through an associated saturating winding 22E, and similarly the inductance of the other reactor winding 216 is controlled by the amount of direct current passed through an associated saturating winding 222.

When there is very little direct current passing through the reactor saturating winding 22L the reactance of the Winding M is large and the alternating current voltage supplied to the transformer winding 2H3 is far out of phase with the alternating current voltage applied to the anodes of the thyratrons 253?, 288. Therefore, the winding 2H8 does not fire the latter tubes until very late in their respective half cycle. The voltage supplied to the motor armature 2M is, therefore, low so that the motor turns at low speed. On the other hand, when the amount of direct current supplied to the saturating winding 22l is increased, the resultant change in reactance in the winding 21%) causesv of respective ones of the bridges.

the voltage across 2l8 to become more in phase with the anode voltage on the thyratrons 201,

Consequently, 2 l 8 fires the Variation of the direct currents supplied to the saturating windings 22L 222 is accomplished through the use of an electronic network (Fig. In brief, the arrangement is such that motor speed is varied by manual adjustment of a pair of potentiometer 223, 224 ganged together for operation in unison. The control portion of each potentiometer is compressed into half the range of angular adjustment the feed motor, as for example in the control pendant I45 as shown in Fig. 15.

work of Fig. 19 is applied from a pair of conductors 23I, 232 which are supplied from a full wave rectifier comprising a twin diode A. The

resistors 1R, BR and. 24R is connected across the lines 23!, 232. The voltages are regulated by tubes B, G which operamount of voltage drop across the resistor 1R depends,in turn, upon how much current is passing through triode tubes C and E. The tube C is employed for varying the drop across the resistor TB in accordance with the setting of the speed control potentiometer 223, whereas the tube E. is employed as part "fier F, a resistor of adjustment of these potentiits adjustment vary the current 201, 200 to the motor tive, changes in passed by the thyratrons armature, while during the range of adjustment. in which the potentiometer 224 is active, it varies the current passed by the thyratrons 209, 2I0 to the motor field 203.

Automatic speed regulation is accomplished by comparing the armature voltage to a standard voltage, the latter being derived from the regulated supply afiorded by the tubes B, G. The difierence between these two voltages is amplified and applied to the grid of the triode D which saturates the reactor H5. The triode C is utilized for that purpose. The armature voltage is applied to the grid of the tube C and as it tends to increase, the grid of the tube becomes less negative thereby turning off the tube C so that the latter tends to turn the tube D off, reducing the current through the saturating winding 22I and diminishing the output of the thyratrons 201, 208. Tendency of the armature voltage to decrease results in an opposite action.

Compensation for changes in IR drop in the armature is desirable since armature speed is proportional to armature terminal voltage only when the armature is drawing no current. Where, as here, armature is used in effecting speed regulation, compensation should, therefore, be made for changes in IR drop to effect accurate regulation. For this purpose, it is necessary to introduce in the armature control circuit a volt- .age proportional to the armature current and in such a direction as voltage as the load that end, a pair of on the motor increases. To coupling transformers having primary windings 23B, 230 in .the anode circuits of thethyratrons 201, 208 are utilized for deriving va current proportional to motor armature current. These primary windings are inductively coupled with secondary windings 240, 2. The pulses-of current through the latter are rectified byfull wave rectifier shown as the duplex recti- 3IR serving to load the secondaries 240, MI. The direct current voltage output of F is proportional to motor armature current and is applied to the network to subtractirom that part of the armature voltage that 'is'used as'a 'feed back, and thus causes a higher voltage to be maintained by the regulating action of the system. Adjustment of potentiometer 226 may be utilized to effect either over or under compounding.

In order to prevent-excessive currents being drawn during starting, other acceleration conditions, .orsudden application of load,,an automatic :current limiting control is. incorporated. The same "direct current potentiometer derived from the rectifier F in proportion to armature current for purposes of IR drop compensation, as

':noted above, is utilized to afford a current-limit signal. For that purpose this signal is compared to a known voltage standard and the difference amplified by the triode E. The point at which the current limit control takes over isadjustable :by'means of the potentiometer 230. As long as the voltage on the slider of this potentiometer is lessthan a predetermined value, the triode E is inoperative and the triode C will have complete control. If higher armature current causes the voltage on the potentiometer slider 230 to reach such predetermined value, the triode E will pass full plate current, thus retarding the phase of *thegrid voltage onthe thyratrons 201, 208. The

to hold a higher armature armature current is thus reduced until 'apoint of balance is reached. With this control, it is possible to accelerate from zero to full speed without drawing more than the preset value or armature current. Normally closed interlock contacts 2P5, 235 on the main reversing contactors 2R, 2F for the feed motor H9 are used to give a false signal in a current limit circuit at starting. When these contacts areboth closed, the condenser IC is charged so that during the first phase cycles after one or the other of the contacts 2F5 or 2R5 opens at starting, potentiometer will be applied to the triode E from the condenser, rendering the triode operative even during the initial period when no armature current signal is available. After the first few cycles, this signal becomes available and operation continues as previously described.

As heretofore noted, the range of speed adjustment is enlarged by making possible control of both the armature and field currents for the feed motor H9. With the potentiometers 223, 224 arranged as heretofore described, the field excitation remains at rated value while the motor speed is being controlled by varying the armature voltage while conversely the armature voltage remains at rated value when operating the motor in the weak field range. In the weak field range, the speed is preset by adjusting the field current, but the regulation is still accomplished through automatic regulation of the armature voltage as heretofore described. The circuit employed for the field control is similar to that for the armature including a triode D' which feeds current to the saturating winding 222 and triodes C and E which, in turn, control the triode D, the same being related in a manner to the triodes C, D and. E heretofore noted. Provision is also made for voltage snubbing and preconditioning through use of a triode J and duplex diode rectifier J. They act to retard the application of field when the armature voltage exceeds a preset amount as, for example, when the speed control potentiometers 223, 220 are suddenly turned from the weak field condition to a speed calling for full field.

The control pendant Operational control is incorporated in one centralized control panel which in the present instance comprises the pendant I45 conveniently suspended at the operators station. Thus, the pendant I45 houses the run switch I18 and the stop switch I10 adjustable either for continuous run or for inching, and the direction control switch I11 for the spindle motor 30. Also mounted on the pendant I 15 are the run switch I84, the latch-type stop switch I85, and the saddle or table selector switch I82 for controlling the drive from the motor I I9, and the run switch I89, the stop switch I and the selector switch I83 for the headstock and table. The master stop switch I14 is located in the pendant I45 adjacent the lower end.

Mounted within the pendant M5 at one side are the potentiometers 223 and 224 having an adjusting shaft 242 extending through the left side wall and operable by a hand wheel 203 journaled on the outside of said wall. The shaft 202 has a pinion 202 thereon meshing with an internal gear 243 rigid with the wheel 203. A stop 203 serves to limit rotation of the wheel 203 to one revolution or slightly less. A similar set of speed-control potentiometers 2'34, 245 for the motor I20 is mounted in the pendant I45, and has an adjusting shaft 206 extending through the side -switches I99 and 200 noids I66 and I61. In the present instance, the

to open the associated toggle switch, olution for the high-speed range at the end of which on the descending scale it is operable to close the toggle switc Mounting of the two sets of potentiometers 223, 224 and 244, 245 in the pendant I45, with their adjusting elements 243 and 241 at opposite sides, is particularly advantageous since it permits the operator, in contouring operations, to grasp and adjust both potentiometer controls simultaneously while holding the pendant I45 in his two hands.

I claim as my invention:

1. A machine comprising, in combination, a support, support, three drive transmissions operatively connected respectively to said units and each having a terminal power inlet shaft, two reversible electric drive motor mounted on said bed and zsaidanotor to said unit to electric control .means for said motor to reverse the .nism for connecting translate said unit, efiecting reversalof direction of translation of said unit, hydraulic .means for adjusting said-speed mechanism, and

electronic-control means for-adjusting the speed of .saidmotorforeitheradjustment of said mechanism, whereby-to translatesaid unit atany speed overa total speed gradient :comprising high and low speed ranges.

8. .A machine (comprising, in zcombination, a support, a machine unit reversibly movable on said support, -a reversible electric drive motor adjustable :in speed over a predetermined finely- -graduated range, a ,drive transmission including an :adjustablehigh and low speed range mechanismior connecting said motor to said unit to translate said unit, a pendant control panel adapted -.to be grasped in the hands of the operator, :remote control means including control elements n said fpanelnfor starting and-stopping said motor and for inching said motor, remote .control means including a control-element onsaid panel for effecting reversal of said motor toreverse the directioniof translation of said unit, electronic control means including a potentiometer in said panel and with an adjusting .knob-on'one side :of said :panel for adjusting the speed of said motor for either range adjustment .of 1 said mechanism, hydraulic means f or adj ust- :ing said mechanism, electric control means for .saidlhydra-ulic means andincluding a range selector switch operable by said potentiometer after 1a ,predetermined rotationofsaid-knob in either direction, whereby :to translate said unit at any speed over a range which is greater than the speed range of said motor.

A :machine comprising, .in combination, a support, a machine unit reversibly :movable on said support, a reversible relectr-ic drive motor adjustable in speed overea predetermined "range, '23, dnive'lt-ransmission including :a separable -con- -nection and an adjustable speed range :mecha- -nismfor connecting :said motor to said'unitxto :translate said 'unit, means for effecting reversal of said motor-toreverse the direction of translantion of sa-id unit, lmeans for-adjusting thespeed of :said :motor including a 'lpotentiometer shaving tan-adjustingiknob, and :means for adjusting said speed rmechanism including an :electric switch operable upon adjustment 10f :said potentiometer in either direction over the full motor speed range.

10. A machinemomprising, lin combination, a support, a machine un't reversibly movable on said support, a reversible electric drive motor adjustable :-in speed over a predetermined range, ,a drive transmission including a'separaible connection and an adjustable speed range mechanism .-f or -:.connecting said :motor to said unit to translate said -unit, means for-effecting reversal of said -mtor toreversethedirection 'of atranslation of said .unit, :means for adjusting the speed 0f :said motor includingta potention'ieter having anedjusting knob -,1= otatable through approximately one revolution or :less to -adjust said potentiometer through'two revolutions with -each-revollut-ion of said potentiometer covering the :full motor speed range, and .meansrfor adjusting said speed mechanism inoludinge reversible electric .rangeselector switch operable by rotationaof said potentiometer substantially at the midpoint :of itsrange of movement.

11.. :A boring machinecomprising,winwcombination, .a support, .a plurality of zmachine :units minal shafts,

.tor, selective coupling means mounted for independent and reversible translation :on said support, a plurality of reversible variable speed drive motors, a-plurality of drive transmissions operatively connected respectively to said units and having terminal power inlet shafts, a plurality of adjustable speed :mechanisms connected'respectively tosaid motors and having outlet power shafts, each mechanism having-high and low speed adj ustments of a .r-atio corresponding to that portion of the speed'range of the associated-motor utilized during high-speed adjustment of said mechanism, and selective coupling means for disengageably connectingsaid power shafts individually to said respective terwhereby to drive said units individually or in various combinations and independently in direction and. rate of speed.

12. A boring machine comprising, in combination, a support, a machine unit mounted aforreversible translation on said support, a plurality of reversible variable speed drive motors, a drive transmission operatively connected to said-unit and having a terminal power inlet shaft, .a'plurality of adjustable speed mechanisms :connected respectively to said motors and having outlet power shafts, each mechanism having highland low speed adjustments of a ratio corresponding to the utilized speed range of the associated'mofor connecting either of said power shafts individuallyto said terminal shaft, and interlock means for :preventing connection of said mechanisms simultaneously to said terminal shaft.

3. A boring machine comprising, incom'bination, a, support, a machine unit mounted for reversible translation on said support, a plurality of reversible variable speed drive motors,.a-=drive transmission operatively connected to said unit and having a terminal power inlet shaft, a 13111- rality of adjustable speed mechanisms connected respectively to said motors and having outlet power shafts, each mechanism having high and low speed adjustments of a ratio corresponding to the speed range of the associated motor, first *and second :coupling means including parallel I withsaid dogs, whereby upon rotation of either operating shaft in a direction to connect the associated power shaft to said terminal shaft the associated rod is actuated to block the other rod against movement in a direction to connect the other power shaft to said terminal shaft.

14. A machine comprising, in combination, a

"support, a machine unit reversibly movable on said support and carrying a rotatable spindle, a

spindle motor for driving said spindle, a reversible feed motor adjustable in speed over a predetermined range, a drive transmissionincluding an adjustable speed mechanism for connecting said feed motor to said unit to translate said unit, means for effecting reversal of said motor to reverse the direction of translation of said unit, hydraulic means for adjusting said speed mechanism, an oil pump forming part of said hydraulic means, an oil pump motor for driving said pump, means for adjusting the speed of said feed motor, interlock means for preventing operation of said spindle motor unless the oil pump :motor is operating, and (interlock means for 'pre- 

